1. Field of the Present Invention
The present invention relates generally to sliding door operators and more particularly to a door operator employing a motor driven gear which engages an elongated rack displaceable with respect to the supporting structure of the sliding door.
2. Description of the Prior Art
Sliding doors are a well known form of closure and various means have been employed for automatically operating the sliding doors. However, the operating mechanism for the sliding doors is often incorporated with the framing structure that supports the sliding door. For example, the bottom edge of the door can be provided with an elongated gear tooth rack which engages a rotatably driven gear supported in the door frame. Such an assembly is disadvantageous for the reason that repair of the door operating mechanism requires disassembly of the entire door structure, and thus substantially increases the complexity and cost of making repairs of the door operator.
It has also been known that a gear driven rack can be mounted on an exposed surface of the door. However, such a construction is disadvantageous for the reason that the appearance of a rack on the exposed portions of the door substantially detracts from the appearance of the door. Moreover, in order to open the door fully, the driven gear must be continuously rotated until the entire rack has been traversed by the gear. Accordingly, energy must be supplied to the gear driving means during the same period of time. As a result, if the door is wide, a substantial amount of energy may be necessary to fully open or fully close the door.
In addition, many previously known door openers are not readily adapted for use with previously installed sliding doors. This problem is especially true of sliding glass doors, commonly known as patio doors, especially since such doors slide in tracks which are often integrally constructed with the building structure. Accordingly, previously known operating mechanisms cannot be readily secured to previously installed patio doors without substantial reconstruction of the mounting track and surrounding structure.